With the fast development of the Internet and broadband access network, live video service can be deployed on the Internet by employing the P2P technology successfully in large scale.
The present system are not compatible of supporting time shift service, namely, a user can not review a program in live broadcasting or watch a program that has been broadcasted. The online live broadcasting service is mainly used on the broadcasting for sports games and entertainment programs. A user often needs to watch a program that has been broadcasted or temporarily review a scene that has been missed. If a system can support time shift service, the demands of users can be better satisfied and the quality of user experience can be promoted.
The above time shift function can be realized by referring to the operation of a personal video recorder, namely, a client terminal records the whole program being watched in a disk. Therefore, when a user selects to play backward, the data in a disk can be played so that the client can watch a previous program, the data in a disk can also be replayed. The method, though very simple, consumes much resources on a client terminal: first, the continuous recording of a video while playing puts much pressure on disk I/O; second, the cost of disk storage is very high, a client terminal should have a big disk space for storing the completed video programs independently; third, the method is applicable for the user to replay a program that has been broadcasted, but it is hard for the user to replay a program that has not yet been watched, which results in a big limit.
The reason for the above limit is that the method tries to let each client terminal finish the above functions independently, resulting in the problem of the high price of realization, namely, both the big costs on storage and pressure on disk I/O. It's undoubtedly ideal if it is possible for a plurality of client terminals to take part in the above functions to complete the time shift service. But the related technology has not yet been realized.